Published by Adrian Vogel · Reading time: approx. 13 minutes · Last updated: October 2026 · Jurisdiction: Germany
Before you start: This article is not financial, investment, insurance or tax advice. All example calculations are our own, for an invented household. They do not predict what will happen.
In short:
- The instalment alone says little. What counts is how much buffer remains when something gets in the way.
- Eight charts to try out: loan amount, repayment, offers, special repayment, repairs, parental leave, incapacity for work, buying versus renting.
- Three views show the same household read-only in the OWNAMIC Big Picture.
- At the end: a comparison table for loan offers and five Excel formulas to check the numbers yourself.
Why the monthly instalment alone is not enough
The bank tells you which instalment you get. Whether you can carry it for 27 years, with a child, a new heating system or a longer illness, is for you to work out. We do that here with an invented household and a chart for every key figure. You can adjust the charts.
| Example household (invented) | |
|---|---|
| Net income | €5,400 a month (€3,200 + €2,200) |
| House, 140 m² | €450,000 plus €45,000 purchase costs |
| Equity | €95,000, leaving a €20,000 reserve |
| Loan | €400,000, 4.10% nominal rate, 2% initial repayment, fixed for 10 years |
| Instalment | €2,033 a month |
| Living and fixed costs | €2,550 plus €250 for maintenance |
| Left each month | €567 |
We calculate cautiously on purpose: income and costs rise by 2% once a year. The house and the savings do not gain value. After the fixed-rate period we assume the same rate. Nobody knows the real follow-up rate today.
This is the same household in the OWNAMIC Big Picture. The view is read-only: you can switch the time span and open the details, but you cannot change anything.
Calculated with 2 % income growth and 2 % inflation a year. Wealth goal, value growth and the entries under “Configure scope” are not set. Once registered, you adjust every assumption to suit you.
tune Assumptions & net worth target expand_more
expand_content Details expand_more
What the carry-forward actually rests on. Every kind of input that is not recorded is calculated as zero and makes the curve too optimistic.
| check_circle | Income | 5,400 € | entire horizon |
| check_circle | Fixed costs | 1,100 € | entire horizon |
| check_circle | Variable costs | 1,700 € | from 0 purchases |
| check_circle | Assets | 470,000 € | |
| check_circle | Debt | 2,033 € | entire horizon |
| remove | Savings plans | none |
functions How this chart is calculated — every formula expand_more
Everything below is computed deterministically from the recorded objects — no AI, no assumptions about markets or prices. Symbols: t = month (0 = today), i = monthly interest rate, σ = assumed standard deviation, g = assumed annual value change of an asset class (0 % unless you set one).
Net worth today
Every active object counts at its documented (purchase-backed) or AI-estimated value: real estate, money and accounts at their recorded balance, financial assets (securities, funds, deposits), digital assets (crypto, tokens, licences), vehicles, collectibles and household goods. The remaining debt of all loans is subtracted. Consumed goods — consumables and cosmetics — are excluded, and a collection is a container that counts only through the objects it holds.
net worth(0) = documented values + estimated values − remaining debt(0)
asset classes: real estate · money · financial assets · digital assets · collectibles · vehicles · householdThe net-worth line
Six effects move the line: the cash surplus or deficit of that month, the loan principal repaid in it, the durable share of variable purchases (a car keeps resale value, groceries do not), the inflation indexation of price-linked objects (real estate, collectibles), the money moved into asset classes by savings plans and planned trades, and — only if you set a rate per class — the assumed value change. Money assets, financial and digital assets, vehicles and household goods stay nominally constant by default. A savings rate leaves the surplus and arrives as a transfer, so the two cancel and the line does not move. The number above the chart is exactly the rise of that line over the selected horizon — the cumulative surplus alone is only one of the effects and has its own tile further down.
net worth(t) = net worth(0) + cumulative surplus(t) + repaid principal(t) + durable share(t) + inflation indexation(t) + transfers into assets(t) + assumed value change(t)Yearly surplus / deficit (the bars)
Income minus expenses minus the full loan installment (interest and principal), any special repayments (Sondertilgung) and the rates of savings plans and planned purchases; sale proceeds count as inflows. A year's bar is the sum of its 12 monthly nets. The full installment, special repayments and savings rates all count as outflows here — the principal inside the installment and the transferred savings are credited back in the line above, never counted twice.
monthly net = income − expenses − loan installment − special repayment − savings rates & planned purchases + sale proceeds
year bar = Σ of the 12 monthly netsWho pays when the bars are red?
A deficit is drawn from the money assets (accounts, savings accounts): their stock shrinks by exactly the accumulated deficit. Net worth can still rise at the same time, because most of the loan installment is not a cost but repayment — money moving from the account into home equity. Only the interest portion truly leaves the wealth. A savings plan works the same way: the rate leaves the account and turns into the asset it bought. If the money assets would drop below zero, the chart stops in that month with a red warning: from there on only a sale of other assets or a new loan could pay the bills, and neither is modelled.
money assets(t) = money assets(0) + cumulative surplus(t) (the surplus is already net of savings rates)
Δ net worth in month t = monthly net + principal(t) + transfers(t) = income − expenses − interest(t)
liquidity used up = first month with money assets(t) < 0 → the chart stops thereLoan repayment (the dashed line)
The remaining-debt line follows a real amortization schedule: each month interest is charged on the current balance, the rest of the installment repays principal. As the balance falls, the interest share shrinks and the repayment share grows. Any recorded special repayments (Sondertilgung) reduce the balance directly on top. Without a recorded installment, the annuity is derived from the contract values (n = term in months). A loan that only starts later in the horizon carries no debt until its start month; then its principal is paid out into the money assets and becomes debt at the same time, and the installments follow from the month after.
i = annual interest rate ÷ 12
interest(t) = balance(t−1) × i
principal(t) = installment − interest(t)
balance(t) = balance(t−1) − principal(t) − special repayment(t)
annuity fallback: installment = loan amount × i ÷ (1 − (1 + i)^−n)The value corridor
An ~80 % confidence band around the expected line. AI-estimated values carry an assumed uncertainty of ±25 %; recurring spending an assumed variation of ±15 % per month — the band widens over time.
corridor(t) = net worth(t) ± 1.2816 × √(t × σ_spending² + σ_estimates²)
σ_estimates = 25 % of AI-estimated values · σ_spending = 15 % of monthly expensesWealth goal
A target you set for your net worth. It never enters the arithmetic — the line does not move because of it. It is drawn as a horizontal dashed line in the net-worth view, not in the category view: there the areas show a composition, not a total. The star marks the crossing with the middle curve, and the vertical dashed line runs from there down to the time axis. The tile states the span in which the goal could be met: the upper end of the uncertainty corridor gives the early year, the lower end the late one.
goal year = first month with curve(t) ≥ goal · span = [upper corridor edge, lower corridor edge]Inflation
The chart shows future euros. Prices — recurring expenses and variable costs — rise with the inflation rate you set, and so do income (at your nominal income growth) and the value of real estate and collectibles. Money assets, financial and digital assets and the mortgage schedule are nominally fixed and stay flat (unless you set a rate per class), which is why savings quietly lose purchasing power while fixed debt gets lighter. Vehicles and household goods are left flat too: they are estimated present values with no depreciation model behind them, and indexing them up would overstate a stock that in reality loses value.
price level(t) = (1 + inflation)^(t/12) · today, real value(t) = nominal value(t) ÷ price level(t)Variable costs (consumables, vehicles, …)
Consumables, vehicles, collectibles and household goods are carried forward from averages of your own purchases over a per-category window (e.g. 6 months for consumables, 7 years for vehicles). The full amount counts as spending; for durables the part that keeps a resale value (retention factor) is credited back as an asset, so net worth reflects depreciation rather than the full outflow.
net-worth impact = spend − retention × spendSavings plans and planned trades
A savings plan is one repeating purchase event with a quantity and an amount per rate; a single planned purchase or sale is the same event without repetition. From tomorrow on, every occurrence inside the horizon moves money: a purchase leaves the money assets — it counts as an outflow in the monthly net, exactly like a loan installment — and lands in the object's asset class at the amount paid. A sale runs the other way. The transfer itself does not move net worth: the line assumes neither gain nor loss on it. Rates are fixed nominal commitments and are never escalated with inflation. Occurrences up to today are already part of the object's value and are not counted again.
monthly net = income − expenses − loan installment − special repayment − savings rates & planned purchases + sale proceeds
asset class(t) = asset class(0) + Σ purchases(≤ t) − Σ sales(≤ t)
Δ net worth caused by a transfer = 0Value development of the asset classes
Every class starts at 0 % per year — no gain, no loss. Real estate and collectibles additionally follow the price level (inflation). If you state a rate for a class under „Configure scope“, today's stock and every transferred tranche compound at it from the month they are held. For comparison the chart derives what your own objects did so far: purchase price against latest valuation, annualized and value-weighted, over at least six months. That figure is read-only and never applied on its own — the past performance of a few objects says nothing about the future.
value(t) = value(0) × (1 + g)^(t/12) · indexed classes additionally × price level(t)
historical g = (latest valuation ÷ purchase price)^(12/months) − 1, value-weighted per class (read-only)Scenarios
A scenario lays a what-if over your real objects: hidden objects drop out, scenario objects are added as if they were recorded, and everything is projected with the same arithmetic. A changed income is split into the time before, inside and after the change. A loan that starts later carries no debt until its month; then its principal lands in the money assets and the same amount becomes debt, so the line does not move on disbursement. Buying an asset moves its price from the money assets into its class in the purchase month; only the ancillary costs are consumed. The grey ghost line is the current state under the same horizon, and the delta tile is the difference at the end.
Income change: S₁ (until start) · S₂ (new amount) · S₃ (after end) · Loan at m: money +L, debt +L · Purchase at m: class +P, money −P, expense +N · Δ = scenario(T) − current state(T)Assumptions and limits
Asset values are held constant — no appreciation or depreciation, no taxes, no investment returns — unless you deliberately set a rate for a class. Market volatility of securities and crypto is not modelled; a savings plan is carried at the amount paid. Not in the carry-forward yet: pending bookings in the transactions inbox, the remaining balance of consumer loans (only their installments count), and the running costs of ownership (repairs, maintenance, fuel). Deficits are funded from the money assets; once those run out, the chart stops in that month and warns — selling other assets or taking out a new loan is not modelled. It describes, it does not advise.
Where each object type lands
Every OWNAMIC object type and how the carry-forward reads it — derived from the same rules the calculation runs on, so this table cannot disagree with the numbers.
| Object type | Assets | Cash flow |
|---|---|---|
| Flexible Physical belongings | Counts at its value: Household | Planned purchases and sales (events with quantity): transfer between money and this class |
| Appliance Physical belongings | Counts at its value: Household | Past purchases: variable costs (Household & electronics) · planned purchases with quantity: transfer |
| Artwork Physical belongings | Counts at its value: Collectibles | Past purchases: variable costs (Collectibles) · planned purchases with quantity: transfer |
| Clothes Physical belongings | Counts at its value: Household | Past purchases: variable costs (Household & electronics) · planned purchases with quantity: transfer |
| Collectible Physical belongings | Counts at its value: Collectibles | Past purchases: variable costs (Collectibles) · planned purchases with quantity: transfer |
| Collection Physical belongings | Counts at its value: Household | Planned purchases and sales (events with quantity): transfer between money and this class |
| Component Physical belongings | Counts at its value: Household | Planned purchases and sales (events with quantity): transfer between money and this class |
| Decoration Physical belongings | Counts at its value: Household | Past purchases: variable costs (Household & electronics) · planned purchases with quantity: transfer |
| Electronic Medium Physical belongings | Counts at its value: Collectibles | Past purchases: variable costs (Collectibles) · planned purchases with quantity: transfer |
| Electronic device Physical belongings | Counts at its value: Household | Past purchases: variable costs (Household & electronics) · planned purchases with quantity: transfer |
| Furniture Physical belongings | Counts at its value: Household | Past purchases: variable costs (Household & electronics) · planned purchases with quantity: transfer |
| Jewlry Physical belongings | Counts at its value: Collectibles | Past purchases: variable costs (Collectibles) · planned purchases with quantity: transfer |
| Literature Physical belongings | Counts at its value: Collectibles | Past purchases: variable costs (Collectibles) · planned purchases with quantity: transfer |
| Material Physical belongings | Counts at its value: Household | Past purchases: variable costs (Consumables) · planned purchases with quantity: transfer |
| Musical Instrument Physical belongings | Counts at its value: Collectibles | Past purchases: variable costs (Collectibles) · planned purchases with quantity: transfer |
| Pet Physical belongings | Counts at its value: Household | Past purchases: variable costs (Household & electronics) · planned purchases with quantity: transfer |
| Plant Physical belongings | Counts at its value: Household | Past purchases: variable costs (Household & electronics) · planned purchases with quantity: transfer |
| Real Estate Physical belongings | Counts at its value: Real estate | Planned purchases and sales (events with quantity): transfer between money and this class |
| Sports Equipment Physical belongings | Counts at its value: Household | Past purchases: variable costs (Household & electronics) · planned purchases with quantity: transfer |
| Tool Physical belongings | Counts at its value: Household | Past purchases: variable costs (Household & electronics) · planned purchases with quantity: transfer |
| Toy Physical belongings | Counts at its value: Household | Past purchases: variable costs (Household & electronics) · planned purchases with quantity: transfer |
| Unknown Physical belongings | Counts at its value: Household | Planned purchases and sales (events with quantity): transfer between money and this class |
| Vehicle Physical belongings | Counts at its value: Vehicles | Past purchases: variable costs (Vehicles) · planned purchases with quantity: transfer |
| Consumable Consumer goods | Not an asset (consumed) | Past purchases: variable costs (Consumables) · planned purchases with quantity: transfer |
| Cosmetics Consumer goods | Not an asset (consumed) | Past purchases: variable costs (Consumables) · planned purchases with quantity: transfer |
| Digital Asset Financial assets | Counts at its value: Digital assets | Planned purchases and sales (events with quantity): transfer between money and this class |
| Financial Asset Financial assets | Counts at its value: Financial assets | Planned purchases and sales (events with quantity): transfer between money and this class |
| Money & Assets Financial assets | Balance as recorded: Money & assets | Source of deficits and savings rates; surpluses accumulate here |
| Mortgage Financial assets | Remaining debt (subtracted) | Loan installment from the amortization schedule, plus special repayments |
| Repayment Financial assets | — | Installment as fixed costwarning Gap: the remaining debt behind it is not modelled yet |
| Gift Income | — | Income or expense, per cost type |
| Salary Income | — | Income (recurring or one-time) |
| Insurance Service expenses | — | Fixed cost (income if the cost type says so) |
| Power or Heat Supply Service expenses | — | Fixed cost (income if the cost type says so) |
| Rent Service expenses | — | Fixed cost (income if the cost type says so) |
| Service Service expenses | — | Recurring: fixed cost · past one-time: variable costs (Services (services, accommodation, travel)) |
| Subscription Service expenses | — | Fixed cost (income if the cost type says so) |
| Tax Service expenses | — | Fixed cost (income if the cost type says so) |
| Accommodation Travel costs | — | Recurring: fixed cost · past one-time: variable costs (Services (services, accommodation, travel)) |
| Transportation Travel costs | — | Recurring: fixed cost · past one-time: variable costs (Services (services, accommodation, travel)) |
The Big Picture calculates a little differently from the charts in this article. There, prices and income rise month by month, and the value of the house grows with inflation. Its curves therefore run above our cautious calculation. The figures in the text come from the cautious calculation.
How high can the instalment be?
Rule of thumb: at most 40% of your net income for the instalment, and about 10% of room between your monthly surplus and the instalment (Verbraucherzentrale NRW, German). For new loans the average was just under 38% at the end of 2025 (Interhyp with data from AFS and the Bundesbank, German). In Austria, 40% was even mandatory until mid-2025 (WKO, German).
At 37.7% our household is right on the average. The chart starts with a bigger house: a €480,000 loan, so 45.2%. Try other amounts.
- Monthly instalment
- €2,440
- Share of net income
- 45.2% above the 40% rule of thumb
- Reserve after the heating
- €13,531 in year 6
- Reserve after 15 years
- €53,168
Values as a table
| Year | €400,000 (example) | €480,000 loan |
|---|---|---|
| 0 | €20,000 | €20,000 |
| 1 | €26,800 | €21,920 |
| 2 | €34,224 | €24,464 |
| 3 | €42,284 | €27,644 |
| 4 | €50,994 | €31,474 |
| 5 | €60,366 | €35,966 |
| 6 | €42,811 | €13,531 |
| 7 | €53,548 | €19,388 |
| 8 | €64,987 | €25,947 |
| 9 | €77,142 | €33,222 |
| 10 | €90,029 | €41,229 |
| 11 | €103,662 | €49,982 |
| 12 | €118,055 | €59,495 |
| 13 | €133,224 | €69,784 |
| 14 | €149,185 | €80,865 |
| 15 | €126,368 | €53,168 |
The difference shows when the heating is due. With a €400,000 loan, €42,811 remain in the account after year 6; with €480,000 only €13,531. So the ratio decides less whether you can buy than how much buffer you keep.
Interest and repayment: where your instalment goes
The instalment stays the same, its content does not. In the first month €1,367 goes to interest and only €667 to repayment. The smaller the balance, the more you repay. Only in year 11 does repayment exceed interest.
After ten years you have paid €145,314 in interest and repaid only €98,686. The biggest lever is the initial repayment:
| Initial repayment | Instalment | Debt-free after | Total interest |
|---|---|---|---|
| 1% | €1,700 | about 40 years | €412,031 |
| 2% | €2,033 | about 27 years | €264,779 |
| 3% | €2,367 | about 21 years | €197,754 |
Calculated with 4.10% over the whole term. Nobody knows the rate after the fixed-rate period today.
Nominal rate or APR?
The nominal rate (Sollzins) is only the price of the money. The annual percentage rate (effektiver Jahreszins) includes every cost the bank knows about (§ 16 PAngV, German), which is why it is the figure to compare. Monthly payment alone turns a 4.10% nominal rate into an APR of 4.18%. Commitment interest and voluntary insurance are not included (Dr. Klein, German).
Two offers for the same €400,000 payout:
| Offer A | Offer B | |
|---|---|---|
| Nominal rate | 3.90% plus 2% discount (Disagio) | 4.10% |
| APR | 4.25% | 4.18% |
| Monthly instalment | €2,007 | €2,033 |
| Balance after 10 years | €308,520 | €301,314 |
- Monthly instalment
- A €2,007B €2,033
- Annual percentage rate
- A 4.25%B 4.18%
- Balance after 10 years
- A €308,520B €301,314
- A costs more by
- €4,022 Instalments plus balance after 10 years, minus payout
Values as a table
| Year | Offer B: 4.10% | Offer A: 3.90% plus 2% discount |
|---|---|---|
| 0 | €400,000 | €408,163 |
| 1 | €391,848 | €399,852 |
| 2 | €383,355 | €391,212 |
| 3 | €374,508 | €382,228 |
| 4 | €365,291 | €372,887 |
| 5 | €355,689 | €363,176 |
| 6 | €345,685 | €353,079 |
| 7 | €335,264 | €342,581 |
| 8 | €324,407 | €331,666 |
| 9 | €313,097 | €320,318 |
| 10 | €301,314 | €308,520 |
A has the lower nominal rate and the smaller instalment. Because of the discount, though, you borrow €408,163 to receive €400,000. Over ten years A is therefore about €4,000 more expensive. That is exactly what the APR reveals. For context: at the start of October 2026 the Biallo index for ten years fixed stood at 4.42% (leinetal24, German).
Try it now
Free for 14 days, no payment details. All you need is your email address.
Registration is subject to our Terms and Conditions and Privacy Notice.
Special repayments: what every extra euro does
A special repayment goes entirely into repayment and lowers your interest from then on. During the fixed-rate period, though, you need a clause in the contract for it (§ 500 BGB, German). So ask for it.
- Debt-free after
- 20.1 years
- Total interest
- €189,050
- Interest saved
- €75,728
- Missing from the reserve
- €5,000 a year; the household saves about 6,800 €
Values as a table
| Year | No special repayment | €5,000 a year |
|---|---|---|
| 0 | €400,000 | €400,000 |
| 1 | €391,848 | €386,848 |
| 2 | €383,355 | €373,146 |
| 3 | €374,508 | €358,872 |
| 4 | €365,291 | €344,002 |
| 5 | €355,689 | €328,510 |
| 6 | €345,685 | €312,372 |
| 7 | €335,264 | €295,559 |
| 8 | €324,407 | €278,043 |
| 9 | €313,097 | €259,796 |
| 10 | €301,314 | €240,786 |
| 11 | €289,039 | €220,982 |
| 12 | €276,251 | €200,351 |
| 13 | €262,929 | €178,857 |
| 14 | €249,050 | €156,466 |
| 15 | €234,591 | €133,139 |
| 16 | €219,529 | €108,838 |
| 17 | €203,837 | €83,522 |
| 18 | €187,489 | €57,147 |
| 19 | €170,458 | €29,671 |
| 20 | €152,716 | €1,047 |
| 21 | €134,233 | €0 |
| 22 | €114,977 | €0 |
| 23 | €94,917 | €0 |
| 24 | €74,019 | €0 |
| 25 | €52,248 | €0 |
| 26 | €29,567 | €0 |
| 27 | €5,938 | €0 |
| 28 | €0 | €0 |
| 29 | €0 | €0 |
| 30 | €0 | €0 |
With €5,000 a year you save €75,729 in interest and are debt-free after just over 20 years instead of 27. With €10,000 it is even €116,231 and 16 years. But the money is missing from the reserve, and our household only puts aside about €6,800 a year. Special repayments only pay off once the buffer is in place.
Repairs: expected and unexpected
As an owner you pay every repair yourself. Heating, roof or windows you can plan with a year and an amount. For a burst pipe and the like you need a running reserve. Common guide values are at least €1 per m² a month, €4 to €5 for older houses (Interhyp, Schwäbisch Hall, both German). The Peters formula gives about €550 a month for our house.
Our household plans €250 a month plus the heating in year 6 (€25,000 at today's prices) and the roof in year 15 (€30,000).
- Net worth after 20 years
- €520,175 With upkeep and repairs
- Net worth after 20 years
- €660,254 Without upkeep
- Too good without repairs
- €140,078 Gap after 20 years
Values as a table
| Year | With upkeep and repairs | Without upkeep |
|---|---|---|
| 0 | €70,000 | €70,000 |
| 1 | €84,952 | €87,952 |
| 2 | €100,869 | €106,929 |
| 3 | €117,777 | €126,958 |
| 4 | €135,703 | €148,068 |
| 5 | €154,678 | €170,290 |
| 6 | €147,126 | €193,653 |
| 7 | €168,284 | €218,189 |
| 8 | €190,579 | €243,930 |
| 9 | €214,045 | €270,911 |
| 10 | €238,715 | €299,166 |
| 11 | €264,623 | €328,731 |
| 12 | €291,804 | €359,642 |
| 13 | €320,295 | €391,938 |
| 14 | €350,135 | €425,659 |
| 15 | €341,777 | €460,843 |
| 16 | €374,431 | €497,535 |
| 17 | €408,553 | €535,776 |
| 18 | €444,189 | €575,612 |
| 19 | €481,381 | €617,089 |
| 20 | €520,175 | €660,254 |
Whatever you do not enter, the Big Picture counts as zero. Without maintenance the curve looks €140,079 too good after 20 years. The data basis in the Big Picture shows you what is still missing.
Less salary: parental leave, part-time, sabbatical
Over 25 years there will almost certainly be phases with less salary. Parental benefit (Elterngeld) replaces 65% of the lost net income, at most €1,800 a month, for 12 to 14 months (FIM portal, German). We calculate two cases:
- Parental leave plus part-time: In year 2, partner B takes a year of parental leave (€1,430 parental benefit) and then works at 60% for three years. On top come €400 of extra costs for the child each month (assumed).
- Sabbatical: In year 4, partner A takes six months of unpaid leave and pays €230 a month for health insurance (assumed).
- Monthly balance on leave
- −€603 Parental leave + part-time
- Lowest balance
- −€26,059 Parental leave + part-time · in year 6
- Reserve after 4 years
- €29,239 Sabbatical
- Sabbatical costs once
- €21,755
Values as a table
| Year | Example household | Parental leave + part-time | Sabbatical |
|---|---|---|---|
| 0 | €20,000 | €20,000 | €20,000 |
| 1 | €26,800 | €26,800 | €26,800 |
| 2 | €34,224 | €19,560 | €34,224 |
| 3 | €42,284 | €11,640 | €42,284 |
| 4 | €50,994 | €4,049 | €29,239 |
| 5 | €60,366 | −€3,205 | €38,611 |
| 6 | €42,811 | −€26,059 | €21,056 |
| 7 | €53,548 | −€20,728 | €31,792 |
| 8 | €64,987 | −€14,803 | €43,231 |
| 9 | €77,142 | −€8,271 | €55,387 |
| 10 | €90,029 | −€1,121 | €68,274 |
| 11 | €103,662 | €6,661 | €81,907 |
| 12 | €118,055 | €15,086 | €96,300 |
| 13 | €133,224 | €24,167 | €111,469 |
| 14 | €149,185 | €33,918 | €127,430 |
| 15 | €126,368 | €4,768 | €104,613 |
During the parental leave about €600 a month is missing. In year 5 the reserve is empty, and with the heating the household would be €26,059 in the red. The sabbatical costs about €21,800 once, but the reserve stays positive. So what matters is how long the money is missing.
In the Big Picture you put a case like this as a scenario next to your real figures. Here is the scenario "Parental leave + part-time", read-only again. The grey line is the household without the leave. If the curve ends early, the liquid assets are used up. The Big Picture does not simply assume an overdraft; it tells you in which year the money runs out.
Calculated with 2 % income growth and 2 % inflation a year. Wealth goal, value growth and the entries under “Configure scope” are not set. Once registered, you adjust every assumption to suit you.
tune Assumptions & net worth target expand_more
From this month on, expenses, installments and savings rates can no longer be paid from the money assets (accounts, savings accounts). Carrying the line further would mean selling other assets or taking out a new loan with interest — the carry-forward models neither, so the chart stops here.
Until then your savings last ≈ 56 months. Still there afterwards: property, securities and physical assets ≈ 494,000 €. Loans outstanding: ≈ 358,000 €.
expand_content Details expand_more
What the carry-forward actually rests on. Every kind of input that is not recorded is calculated as zero and makes the curve too optimistic.
| check_circle | Income | 5,400 € | entire horizon |
| check_circle | Fixed costs | 1,100 € | entire horizon |
| check_circle | Variable costs | 1,700 € | from 0 purchases |
| check_circle | Assets | 470,000 € | |
| check_circle | Debt | 2,033 € | entire horizon |
| remove | Savings plans | none |
functions How this chart is calculated — every formula expand_more
Everything below is computed deterministically from the recorded objects — no AI, no assumptions about markets or prices. Symbols: t = month (0 = today), i = monthly interest rate, σ = assumed standard deviation, g = assumed annual value change of an asset class (0 % unless you set one).
Net worth today
Every active object counts at its documented (purchase-backed) or AI-estimated value: real estate, money and accounts at their recorded balance, financial assets (securities, funds, deposits), digital assets (crypto, tokens, licences), vehicles, collectibles and household goods. The remaining debt of all loans is subtracted. Consumed goods — consumables and cosmetics — are excluded, and a collection is a container that counts only through the objects it holds.
net worth(0) = documented values + estimated values − remaining debt(0)
asset classes: real estate · money · financial assets · digital assets · collectibles · vehicles · householdThe net-worth line
Six effects move the line: the cash surplus or deficit of that month, the loan principal repaid in it, the durable share of variable purchases (a car keeps resale value, groceries do not), the inflation indexation of price-linked objects (real estate, collectibles), the money moved into asset classes by savings plans and planned trades, and — only if you set a rate per class — the assumed value change. Money assets, financial and digital assets, vehicles and household goods stay nominally constant by default. A savings rate leaves the surplus and arrives as a transfer, so the two cancel and the line does not move. The number above the chart is exactly the rise of that line over the selected horizon — the cumulative surplus alone is only one of the effects and has its own tile further down.
net worth(t) = net worth(0) + cumulative surplus(t) + repaid principal(t) + durable share(t) + inflation indexation(t) + transfers into assets(t) + assumed value change(t)Yearly surplus / deficit (the bars)
Income minus expenses minus the full loan installment (interest and principal), any special repayments (Sondertilgung) and the rates of savings plans and planned purchases; sale proceeds count as inflows. A year's bar is the sum of its 12 monthly nets. The full installment, special repayments and savings rates all count as outflows here — the principal inside the installment and the transferred savings are credited back in the line above, never counted twice.
monthly net = income − expenses − loan installment − special repayment − savings rates & planned purchases + sale proceeds
year bar = Σ of the 12 monthly netsWho pays when the bars are red?
A deficit is drawn from the money assets (accounts, savings accounts): their stock shrinks by exactly the accumulated deficit. Net worth can still rise at the same time, because most of the loan installment is not a cost but repayment — money moving from the account into home equity. Only the interest portion truly leaves the wealth. A savings plan works the same way: the rate leaves the account and turns into the asset it bought. If the money assets would drop below zero, the chart stops in that month with a red warning: from there on only a sale of other assets or a new loan could pay the bills, and neither is modelled.
money assets(t) = money assets(0) + cumulative surplus(t) (the surplus is already net of savings rates)
Δ net worth in month t = monthly net + principal(t) + transfers(t) = income − expenses − interest(t)
liquidity used up = first month with money assets(t) < 0 → the chart stops thereLoan repayment (the dashed line)
The remaining-debt line follows a real amortization schedule: each month interest is charged on the current balance, the rest of the installment repays principal. As the balance falls, the interest share shrinks and the repayment share grows. Any recorded special repayments (Sondertilgung) reduce the balance directly on top. Without a recorded installment, the annuity is derived from the contract values (n = term in months). A loan that only starts later in the horizon carries no debt until its start month; then its principal is paid out into the money assets and becomes debt at the same time, and the installments follow from the month after.
i = annual interest rate ÷ 12
interest(t) = balance(t−1) × i
principal(t) = installment − interest(t)
balance(t) = balance(t−1) − principal(t) − special repayment(t)
annuity fallback: installment = loan amount × i ÷ (1 − (1 + i)^−n)The value corridor
An ~80 % confidence band around the expected line. AI-estimated values carry an assumed uncertainty of ±25 %; recurring spending an assumed variation of ±15 % per month — the band widens over time.
corridor(t) = net worth(t) ± 1.2816 × √(t × σ_spending² + σ_estimates²)
σ_estimates = 25 % of AI-estimated values · σ_spending = 15 % of monthly expensesWealth goal
A target you set for your net worth. It never enters the arithmetic — the line does not move because of it. It is drawn as a horizontal dashed line in the net-worth view, not in the category view: there the areas show a composition, not a total. The star marks the crossing with the middle curve, and the vertical dashed line runs from there down to the time axis. The tile states the span in which the goal could be met: the upper end of the uncertainty corridor gives the early year, the lower end the late one.
goal year = first month with curve(t) ≥ goal · span = [upper corridor edge, lower corridor edge]Inflation
The chart shows future euros. Prices — recurring expenses and variable costs — rise with the inflation rate you set, and so do income (at your nominal income growth) and the value of real estate and collectibles. Money assets, financial and digital assets and the mortgage schedule are nominally fixed and stay flat (unless you set a rate per class), which is why savings quietly lose purchasing power while fixed debt gets lighter. Vehicles and household goods are left flat too: they are estimated present values with no depreciation model behind them, and indexing them up would overstate a stock that in reality loses value.
price level(t) = (1 + inflation)^(t/12) · today, real value(t) = nominal value(t) ÷ price level(t)Variable costs (consumables, vehicles, …)
Consumables, vehicles, collectibles and household goods are carried forward from averages of your own purchases over a per-category window (e.g. 6 months for consumables, 7 years for vehicles). The full amount counts as spending; for durables the part that keeps a resale value (retention factor) is credited back as an asset, so net worth reflects depreciation rather than the full outflow.
net-worth impact = spend − retention × spendSavings plans and planned trades
A savings plan is one repeating purchase event with a quantity and an amount per rate; a single planned purchase or sale is the same event without repetition. From tomorrow on, every occurrence inside the horizon moves money: a purchase leaves the money assets — it counts as an outflow in the monthly net, exactly like a loan installment — and lands in the object's asset class at the amount paid. A sale runs the other way. The transfer itself does not move net worth: the line assumes neither gain nor loss on it. Rates are fixed nominal commitments and are never escalated with inflation. Occurrences up to today are already part of the object's value and are not counted again.
monthly net = income − expenses − loan installment − special repayment − savings rates & planned purchases + sale proceeds
asset class(t) = asset class(0) + Σ purchases(≤ t) − Σ sales(≤ t)
Δ net worth caused by a transfer = 0Value development of the asset classes
Every class starts at 0 % per year — no gain, no loss. Real estate and collectibles additionally follow the price level (inflation). If you state a rate for a class under „Configure scope“, today's stock and every transferred tranche compound at it from the month they are held. For comparison the chart derives what your own objects did so far: purchase price against latest valuation, annualized and value-weighted, over at least six months. That figure is read-only and never applied on its own — the past performance of a few objects says nothing about the future.
value(t) = value(0) × (1 + g)^(t/12) · indexed classes additionally × price level(t)
historical g = (latest valuation ÷ purchase price)^(12/months) − 1, value-weighted per class (read-only)Scenarios
A scenario lays a what-if over your real objects: hidden objects drop out, scenario objects are added as if they were recorded, and everything is projected with the same arithmetic. A changed income is split into the time before, inside and after the change. A loan that starts later carries no debt until its month; then its principal lands in the money assets and the same amount becomes debt, so the line does not move on disbursement. Buying an asset moves its price from the money assets into its class in the purchase month; only the ancillary costs are consumed. The grey ghost line is the current state under the same horizon, and the delta tile is the difference at the end.
Income change: S₁ (until start) · S₂ (new amount) · S₃ (after end) · Loan at m: money +L, debt +L · Purchase at m: class +P, money −P, expense +N · Δ = scenario(T) − current state(T)Assumptions and limits
Asset values are held constant — no appreciation or depreciation, no taxes, no investment returns — unless you deliberately set a rate for a class. Market volatility of securities and crypto is not modelled; a savings plan is carried at the amount paid. Not in the carry-forward yet: pending bookings in the transactions inbox, the remaining balance of consumer loans (only their installments count), and the running costs of ownership (repairs, maintenance, fuel). Deficits are funded from the money assets; once those run out, the chart stops in that month and warns — selling other assets or taking out a new loan is not modelled. It describes, it does not advise.
Where each object type lands
Every OWNAMIC object type and how the carry-forward reads it — derived from the same rules the calculation runs on, so this table cannot disagree with the numbers.
| Object type | Assets | Cash flow |
|---|---|---|
| Flexible Physical belongings | Counts at its value: Household | Planned purchases and sales (events with quantity): transfer between money and this class |
| Appliance Physical belongings | Counts at its value: Household | Past purchases: variable costs (Household & electronics) · planned purchases with quantity: transfer |
| Artwork Physical belongings | Counts at its value: Collectibles | Past purchases: variable costs (Collectibles) · planned purchases with quantity: transfer |
| Clothes Physical belongings | Counts at its value: Household | Past purchases: variable costs (Household & electronics) · planned purchases with quantity: transfer |
| Collectible Physical belongings | Counts at its value: Collectibles | Past purchases: variable costs (Collectibles) · planned purchases with quantity: transfer |
| Collection Physical belongings | Counts at its value: Household | Planned purchases and sales (events with quantity): transfer between money and this class |
| Component Physical belongings | Counts at its value: Household | Planned purchases and sales (events with quantity): transfer between money and this class |
| Decoration Physical belongings | Counts at its value: Household | Past purchases: variable costs (Household & electronics) · planned purchases with quantity: transfer |
| Electronic Medium Physical belongings | Counts at its value: Collectibles | Past purchases: variable costs (Collectibles) · planned purchases with quantity: transfer |
| Electronic device Physical belongings | Counts at its value: Household | Past purchases: variable costs (Household & electronics) · planned purchases with quantity: transfer |
| Furniture Physical belongings | Counts at its value: Household | Past purchases: variable costs (Household & electronics) · planned purchases with quantity: transfer |
| Jewlry Physical belongings | Counts at its value: Collectibles | Past purchases: variable costs (Collectibles) · planned purchases with quantity: transfer |
| Literature Physical belongings | Counts at its value: Collectibles | Past purchases: variable costs (Collectibles) · planned purchases with quantity: transfer |
| Material Physical belongings | Counts at its value: Household | Past purchases: variable costs (Consumables) · planned purchases with quantity: transfer |
| Musical Instrument Physical belongings | Counts at its value: Collectibles | Past purchases: variable costs (Collectibles) · planned purchases with quantity: transfer |
| Pet Physical belongings | Counts at its value: Household | Past purchases: variable costs (Household & electronics) · planned purchases with quantity: transfer |
| Plant Physical belongings | Counts at its value: Household | Past purchases: variable costs (Household & electronics) · planned purchases with quantity: transfer |
| Real Estate Physical belongings | Counts at its value: Real estate | Planned purchases and sales (events with quantity): transfer between money and this class |
| Sports Equipment Physical belongings | Counts at its value: Household | Past purchases: variable costs (Household & electronics) · planned purchases with quantity: transfer |
| Tool Physical belongings | Counts at its value: Household | Past purchases: variable costs (Household & electronics) · planned purchases with quantity: transfer |
| Toy Physical belongings | Counts at its value: Household | Past purchases: variable costs (Household & electronics) · planned purchases with quantity: transfer |
| Unknown Physical belongings | Counts at its value: Household | Planned purchases and sales (events with quantity): transfer between money and this class |
| Vehicle Physical belongings | Counts at its value: Vehicles | Past purchases: variable costs (Vehicles) · planned purchases with quantity: transfer |
| Consumable Consumer goods | Not an asset (consumed) | Past purchases: variable costs (Consumables) · planned purchases with quantity: transfer |
| Cosmetics Consumer goods | Not an asset (consumed) | Past purchases: variable costs (Consumables) · planned purchases with quantity: transfer |
| Digital Asset Financial assets | Counts at its value: Digital assets | Planned purchases and sales (events with quantity): transfer between money and this class |
| Financial Asset Financial assets | Counts at its value: Financial assets | Planned purchases and sales (events with quantity): transfer between money and this class |
| Money & Assets Financial assets | Balance as recorded: Money & assets | Source of deficits and savings rates; surpluses accumulate here |
| Mortgage Financial assets | Remaining debt (subtracted) | Loan installment from the amortization schedule, plus special repayments |
| Repayment Financial assets | — | Installment as fixed costwarning Gap: the remaining debt behind it is not modelled yet |
| Gift Income | — | Income or expense, per cost type |
| Salary Income | — | Income (recurring or one-time) |
| Insurance Service expenses | — | Fixed cost (income if the cost type says so) |
| Power or Heat Supply Service expenses | — | Fixed cost (income if the cost type says so) |
| Rent Service expenses | — | Fixed cost (income if the cost type says so) |
| Service Service expenses | — | Recurring: fixed cost · past one-time: variable costs (Services (services, accommodation, travel)) |
| Subscription Service expenses | — | Fixed cost (income if the cost type says so) |
| Tax Service expenses | — | Fixed cost (income if the cost type says so) |
| Accommodation Travel costs | — | Recurring: fixed cost · past one-time: variable costs (Services (services, accommodation, travel)) |
| Transportation Travel costs | — | Recurring: fixed cost · past one-time: variable costs (Services (services, accommodation, travel)) |
Here, too, the values run a little above our calculation, partly because the Big Picture lets the parental benefit grow with income. The year in which the reserve is empty is the same: year 5.
Unable to work: what happens to the instalment?
After six weeks of continued pay, the health insurer pays sickness benefit (Krankengeld): 70% of gross pay, at most 90% of net pay, for at most 78 weeks within three years for the same illness (Stiftung Warentest, German). After that, in the worst case, only the statutory disability pension (Erwerbsminderungsrente) remains. New full pensions averaged €1,067 in 2025 (gegen-hartz.de with DRV figures, German). It is not rare: depending on the occupation, one in four to one in six privately insured people becomes unable to work in their occupation at least once during their working life (DAV, German).
In the example, partner A stops working for good from year 3. In the variant there is also a €2,000 private disability pension for a €90 monthly premium (assumed).
- On sickness benefit
- −€138 Monthly balance
- On disability pension
- −€1,603 Monthly balance
- Reserve after 10 years
- −€122,667 Unable to work
- Reserve after 10 years
- €22,533 With disability cover
Values as a table
| Year | Example household | Unable to work | With disability cover |
|---|---|---|---|
| 0 | €20,000 | €20,000 | €20,000 |
| 1 | €26,800 | €26,800 | €25,720 |
| 2 | €34,224 | €34,224 | €32,064 |
| 3 | €42,284 | €34,192 | €30,952 |
| 4 | €50,994 | €23,673 | €31,353 |
| 5 | €60,366 | €4,283 | €34,883 |
| 6 | €42,811 | −€42,864 | €10,656 |
| 7 | €53,548 | −€62,568 | €13,872 |
| 8 | €64,987 | −€82,435 | €16,925 |
| 9 | €77,142 | −€102,467 | €19,813 |
| 10 | €90,029 | −€122,667 | €22,533 |
On sickness benefit only about €140 a month is missing; on the disability pension it is €1,600. In year 6 the reserve is gone. With the private pension the account stays positive.
The same scenario in the Big Picture, without the private pension:
Calculated with 2 % income growth and 2 % inflation a year. Wealth goal, value growth and the entries under “Configure scope” are not set. Once registered, you adjust every assumption to suit you.
tune Assumptions & net worth target expand_more
From this month on, expenses, installments and savings rates can no longer be paid from the money assets (accounts, savings accounts). Carrying the line further would mean selling other assets or taking out a new loan with interest — the carry-forward models neither, so the chart stops here.
Until then your savings last ≈ 65 months. Still there afterwards: property, securities and physical assets ≈ 502,000 €. Loans outstanding: ≈ 351,000 €.
expand_content Details expand_more
What the carry-forward actually rests on. Every kind of input that is not recorded is calculated as zero and makes the curve too optimistic.
| check_circle | Income | 5,400 € | entire horizon |
| check_circle | Fixed costs | 1,100 € | entire horizon |
| check_circle | Variable costs | 1,700 € | from 0 purchases |
| check_circle | Assets | 470,000 € | |
| check_circle | Debt | 2,033 € | entire horizon |
| remove | Savings plans | none |
functions How this chart is calculated — every formula expand_more
Everything below is computed deterministically from the recorded objects — no AI, no assumptions about markets or prices. Symbols: t = month (0 = today), i = monthly interest rate, σ = assumed standard deviation, g = assumed annual value change of an asset class (0 % unless you set one).
Net worth today
Every active object counts at its documented (purchase-backed) or AI-estimated value: real estate, money and accounts at their recorded balance, financial assets (securities, funds, deposits), digital assets (crypto, tokens, licences), vehicles, collectibles and household goods. The remaining debt of all loans is subtracted. Consumed goods — consumables and cosmetics — are excluded, and a collection is a container that counts only through the objects it holds.
net worth(0) = documented values + estimated values − remaining debt(0)
asset classes: real estate · money · financial assets · digital assets · collectibles · vehicles · householdThe net-worth line
Six effects move the line: the cash surplus or deficit of that month, the loan principal repaid in it, the durable share of variable purchases (a car keeps resale value, groceries do not), the inflation indexation of price-linked objects (real estate, collectibles), the money moved into asset classes by savings plans and planned trades, and — only if you set a rate per class — the assumed value change. Money assets, financial and digital assets, vehicles and household goods stay nominally constant by default. A savings rate leaves the surplus and arrives as a transfer, so the two cancel and the line does not move. The number above the chart is exactly the rise of that line over the selected horizon — the cumulative surplus alone is only one of the effects and has its own tile further down.
net worth(t) = net worth(0) + cumulative surplus(t) + repaid principal(t) + durable share(t) + inflation indexation(t) + transfers into assets(t) + assumed value change(t)Yearly surplus / deficit (the bars)
Income minus expenses minus the full loan installment (interest and principal), any special repayments (Sondertilgung) and the rates of savings plans and planned purchases; sale proceeds count as inflows. A year's bar is the sum of its 12 monthly nets. The full installment, special repayments and savings rates all count as outflows here — the principal inside the installment and the transferred savings are credited back in the line above, never counted twice.
monthly net = income − expenses − loan installment − special repayment − savings rates & planned purchases + sale proceeds
year bar = Σ of the 12 monthly netsWho pays when the bars are red?
A deficit is drawn from the money assets (accounts, savings accounts): their stock shrinks by exactly the accumulated deficit. Net worth can still rise at the same time, because most of the loan installment is not a cost but repayment — money moving from the account into home equity. Only the interest portion truly leaves the wealth. A savings plan works the same way: the rate leaves the account and turns into the asset it bought. If the money assets would drop below zero, the chart stops in that month with a red warning: from there on only a sale of other assets or a new loan could pay the bills, and neither is modelled.
money assets(t) = money assets(0) + cumulative surplus(t) (the surplus is already net of savings rates)
Δ net worth in month t = monthly net + principal(t) + transfers(t) = income − expenses − interest(t)
liquidity used up = first month with money assets(t) < 0 → the chart stops thereLoan repayment (the dashed line)
The remaining-debt line follows a real amortization schedule: each month interest is charged on the current balance, the rest of the installment repays principal. As the balance falls, the interest share shrinks and the repayment share grows. Any recorded special repayments (Sondertilgung) reduce the balance directly on top. Without a recorded installment, the annuity is derived from the contract values (n = term in months). A loan that only starts later in the horizon carries no debt until its start month; then its principal is paid out into the money assets and becomes debt at the same time, and the installments follow from the month after.
i = annual interest rate ÷ 12
interest(t) = balance(t−1) × i
principal(t) = installment − interest(t)
balance(t) = balance(t−1) − principal(t) − special repayment(t)
annuity fallback: installment = loan amount × i ÷ (1 − (1 + i)^−n)The value corridor
An ~80 % confidence band around the expected line. AI-estimated values carry an assumed uncertainty of ±25 %; recurring spending an assumed variation of ±15 % per month — the band widens over time.
corridor(t) = net worth(t) ± 1.2816 × √(t × σ_spending² + σ_estimates²)
σ_estimates = 25 % of AI-estimated values · σ_spending = 15 % of monthly expensesWealth goal
A target you set for your net worth. It never enters the arithmetic — the line does not move because of it. It is drawn as a horizontal dashed line in the net-worth view, not in the category view: there the areas show a composition, not a total. The star marks the crossing with the middle curve, and the vertical dashed line runs from there down to the time axis. The tile states the span in which the goal could be met: the upper end of the uncertainty corridor gives the early year, the lower end the late one.
goal year = first month with curve(t) ≥ goal · span = [upper corridor edge, lower corridor edge]Inflation
The chart shows future euros. Prices — recurring expenses and variable costs — rise with the inflation rate you set, and so do income (at your nominal income growth) and the value of real estate and collectibles. Money assets, financial and digital assets and the mortgage schedule are nominally fixed and stay flat (unless you set a rate per class), which is why savings quietly lose purchasing power while fixed debt gets lighter. Vehicles and household goods are left flat too: they are estimated present values with no depreciation model behind them, and indexing them up would overstate a stock that in reality loses value.
price level(t) = (1 + inflation)^(t/12) · today, real value(t) = nominal value(t) ÷ price level(t)Variable costs (consumables, vehicles, …)
Consumables, vehicles, collectibles and household goods are carried forward from averages of your own purchases over a per-category window (e.g. 6 months for consumables, 7 years for vehicles). The full amount counts as spending; for durables the part that keeps a resale value (retention factor) is credited back as an asset, so net worth reflects depreciation rather than the full outflow.
net-worth impact = spend − retention × spendSavings plans and planned trades
A savings plan is one repeating purchase event with a quantity and an amount per rate; a single planned purchase or sale is the same event without repetition. From tomorrow on, every occurrence inside the horizon moves money: a purchase leaves the money assets — it counts as an outflow in the monthly net, exactly like a loan installment — and lands in the object's asset class at the amount paid. A sale runs the other way. The transfer itself does not move net worth: the line assumes neither gain nor loss on it. Rates are fixed nominal commitments and are never escalated with inflation. Occurrences up to today are already part of the object's value and are not counted again.
monthly net = income − expenses − loan installment − special repayment − savings rates & planned purchases + sale proceeds
asset class(t) = asset class(0) + Σ purchases(≤ t) − Σ sales(≤ t)
Δ net worth caused by a transfer = 0Value development of the asset classes
Every class starts at 0 % per year — no gain, no loss. Real estate and collectibles additionally follow the price level (inflation). If you state a rate for a class under „Configure scope“, today's stock and every transferred tranche compound at it from the month they are held. For comparison the chart derives what your own objects did so far: purchase price against latest valuation, annualized and value-weighted, over at least six months. That figure is read-only and never applied on its own — the past performance of a few objects says nothing about the future.
value(t) = value(0) × (1 + g)^(t/12) · indexed classes additionally × price level(t)
historical g = (latest valuation ÷ purchase price)^(12/months) − 1, value-weighted per class (read-only)Scenarios
A scenario lays a what-if over your real objects: hidden objects drop out, scenario objects are added as if they were recorded, and everything is projected with the same arithmetic. A changed income is split into the time before, inside and after the change. A loan that starts later carries no debt until its month; then its principal lands in the money assets and the same amount becomes debt, so the line does not move on disbursement. Buying an asset moves its price from the money assets into its class in the purchase month; only the ancillary costs are consumed. The grey ghost line is the current state under the same horizon, and the delta tile is the difference at the end.
Income change: S₁ (until start) · S₂ (new amount) · S₃ (after end) · Loan at m: money +L, debt +L · Purchase at m: class +P, money −P, expense +N · Δ = scenario(T) − current state(T)Assumptions and limits
Asset values are held constant — no appreciation or depreciation, no taxes, no investment returns — unless you deliberately set a rate for a class. Market volatility of securities and crypto is not modelled; a savings plan is carried at the amount paid. Not in the carry-forward yet: pending bookings in the transactions inbox, the remaining balance of consumer loans (only their installments count), and the running costs of ownership (repairs, maintenance, fuel). Deficits are funded from the money assets; once those run out, the chart stops in that month and warns — selling other assets or taking out a new loan is not modelled. It describes, it does not advise.
Where each object type lands
Every OWNAMIC object type and how the carry-forward reads it — derived from the same rules the calculation runs on, so this table cannot disagree with the numbers.
| Object type | Assets | Cash flow |
|---|---|---|
| Flexible Physical belongings | Counts at its value: Household | Planned purchases and sales (events with quantity): transfer between money and this class |
| Appliance Physical belongings | Counts at its value: Household | Past purchases: variable costs (Household & electronics) · planned purchases with quantity: transfer |
| Artwork Physical belongings | Counts at its value: Collectibles | Past purchases: variable costs (Collectibles) · planned purchases with quantity: transfer |
| Clothes Physical belongings | Counts at its value: Household | Past purchases: variable costs (Household & electronics) · planned purchases with quantity: transfer |
| Collectible Physical belongings | Counts at its value: Collectibles | Past purchases: variable costs (Collectibles) · planned purchases with quantity: transfer |
| Collection Physical belongings | Counts at its value: Household | Planned purchases and sales (events with quantity): transfer between money and this class |
| Component Physical belongings | Counts at its value: Household | Planned purchases and sales (events with quantity): transfer between money and this class |
| Decoration Physical belongings | Counts at its value: Household | Past purchases: variable costs (Household & electronics) · planned purchases with quantity: transfer |
| Electronic Medium Physical belongings | Counts at its value: Collectibles | Past purchases: variable costs (Collectibles) · planned purchases with quantity: transfer |
| Electronic device Physical belongings | Counts at its value: Household | Past purchases: variable costs (Household & electronics) · planned purchases with quantity: transfer |
| Furniture Physical belongings | Counts at its value: Household | Past purchases: variable costs (Household & electronics) · planned purchases with quantity: transfer |
| Jewlry Physical belongings | Counts at its value: Collectibles | Past purchases: variable costs (Collectibles) · planned purchases with quantity: transfer |
| Literature Physical belongings | Counts at its value: Collectibles | Past purchases: variable costs (Collectibles) · planned purchases with quantity: transfer |
| Material Physical belongings | Counts at its value: Household | Past purchases: variable costs (Consumables) · planned purchases with quantity: transfer |
| Musical Instrument Physical belongings | Counts at its value: Collectibles | Past purchases: variable costs (Collectibles) · planned purchases with quantity: transfer |
| Pet Physical belongings | Counts at its value: Household | Past purchases: variable costs (Household & electronics) · planned purchases with quantity: transfer |
| Plant Physical belongings | Counts at its value: Household | Past purchases: variable costs (Household & electronics) · planned purchases with quantity: transfer |
| Real Estate Physical belongings | Counts at its value: Real estate | Planned purchases and sales (events with quantity): transfer between money and this class |
| Sports Equipment Physical belongings | Counts at its value: Household | Past purchases: variable costs (Household & electronics) · planned purchases with quantity: transfer |
| Tool Physical belongings | Counts at its value: Household | Past purchases: variable costs (Household & electronics) · planned purchases with quantity: transfer |
| Toy Physical belongings | Counts at its value: Household | Past purchases: variable costs (Household & electronics) · planned purchases with quantity: transfer |
| Unknown Physical belongings | Counts at its value: Household | Planned purchases and sales (events with quantity): transfer between money and this class |
| Vehicle Physical belongings | Counts at its value: Vehicles | Past purchases: variable costs (Vehicles) · planned purchases with quantity: transfer |
| Consumable Consumer goods | Not an asset (consumed) | Past purchases: variable costs (Consumables) · planned purchases with quantity: transfer |
| Cosmetics Consumer goods | Not an asset (consumed) | Past purchases: variable costs (Consumables) · planned purchases with quantity: transfer |
| Digital Asset Financial assets | Counts at its value: Digital assets | Planned purchases and sales (events with quantity): transfer between money and this class |
| Financial Asset Financial assets | Counts at its value: Financial assets | Planned purchases and sales (events with quantity): transfer between money and this class |
| Money & Assets Financial assets | Balance as recorded: Money & assets | Source of deficits and savings rates; surpluses accumulate here |
| Mortgage Financial assets | Remaining debt (subtracted) | Loan installment from the amortization schedule, plus special repayments |
| Repayment Financial assets | — | Installment as fixed costwarning Gap: the remaining debt behind it is not modelled yet |
| Gift Income | — | Income or expense, per cost type |
| Salary Income | — | Income (recurring or one-time) |
| Insurance Service expenses | — | Fixed cost (income if the cost type says so) |
| Power or Heat Supply Service expenses | — | Fixed cost (income if the cost type says so) |
| Rent Service expenses | — | Fixed cost (income if the cost type says so) |
| Service Service expenses | — | Recurring: fixed cost · past one-time: variable costs (Services (services, accommodation, travel)) |
| Subscription Service expenses | — | Fixed cost (income if the cost type says so) |
| Tax Service expenses | — | Fixed cost (income if the cost type says so) |
| Accommodation Travel costs | — | Recurring: fixed cost · past one-time: variable costs (Services (services, accommodation, travel)) |
| Transportation Travel costs | — | Recurring: fixed cost · past one-time: variable costs (Services (services, accommodation, travel)) |
The Big Picture, too, sees the liquid assets used up in year 6.
Cover at a glance (a description, not a recommendation):
| Cover | Pays out when | Verbraucherzentrale's assessment |
|---|---|---|
| Occupational disability insurance (BU) | You can no longer work in your occupation | "first choice" to protect your earning power |
| Term life insurance | Death, paid to the survivors | sensible to protect dependants |
| Payment protection insurance | depending on the contract, death, incapacity or job loss | "expensive and rarely pays out" |
Source: Verbraucherzentrale (German). OWNAMIC gives no insurance advice. Independent advice is available, for example, from the Verbraucherzentrale.
What the loan does to your net worth
Every repayment raises your net worth. Interest and the €45,000 purchase costs, on the other hand, are gone. Owners with a loan had a median net worth of €379,900 in 2023, renters €18,300 (Bundesbank PHF 2023 via Richify, German). But that proves little: people who can buy often had more to begin with.
Hence the fair comparison: the same household as renters, paying €1,600 cold rent (plus 2% a year). The renters keep their €115,000 and save the difference to the loan instalment, without interest.
- Net worth after 10 years
- Buy €238,715Rent €279,246
- Buying is ahead
- from year 18
- Net worth after 30 years
- Buy €1,003,759Rent €723,521
Values as a table
| Year | Buying with a loan | Renting, 1,600 € cold rent |
|---|---|---|
| 0 | €70,000 | €115,000 |
| 1 | €84,952 | €130,000 |
| 2 | €100,869 | €145,300 |
| 3 | €117,777 | €160,906 |
| 4 | €135,703 | €176,824 |
| 5 | €154,678 | €193,061 |
| 6 | €147,126 | €209,622 |
| 7 | €168,284 | €226,514 |
| 8 | €190,579 | €243,745 |
| 9 | €214,045 | €261,319 |
| 10 | €238,715 | €279,246 |
| 11 | €264,623 | €297,531 |
| 12 | €291,804 | €316,181 |
| 13 | €320,295 | €335,205 |
| 14 | €350,135 | €354,609 |
| 15 | €341,777 | €374,401 |
| 16 | €374,431 | €394,589 |
| 17 | €408,553 | €415,181 |
| 18 | €444,189 | €436,185 |
| 19 | €481,381 | €457,608 |
| 20 | €520,175 | €479,461 |
| 21 | €560,620 | €501,750 |
| 22 | €602,765 | €524,485 |
| 23 | €646,659 | €547,674 |
| 24 | €692,357 | €571,328 |
| 25 | €739,911 | €595,454 |
| 26 | €789,379 | €620,064 |
| 27 | €840,818 | €645,165 |
| 28 | €894,033 | €670,768 |
| 29 | €948,353 | €696,884 |
| 30 | €1,003,759 | €723,521 |
Buying only pulls ahead after 18 years, mainly because the instalment stays fixed while the rent rises. That only holds if the renters really save and the house gains no value. And: the buyer's wealth sits in the house, while the instalment comes out of the account.
Compare loan offers independently
Offers from different banks can be more than €100,000 apart. In the Finanztest field test, only 4 of 19 institutions made mostly good offers (Stiftung Warentest, German). How to compare:
- Set the key figures yourself: amount, fixed-rate period, repayment, special repayment.
- Get at least three offers: your own bank, another bank, a broker.
- Ask for the ESIS sheet. It has the same structure at every bank (ODDO BHF, German).
- Compare APR and remaining balance, not the instalment.
- Check the small print: special repayment, changing the repayment rate, commitment-free period, mandatory insurance.
- Get a second opinion, for example from the Verbraucherzentrale (German).
To fill in, one row per offer:
| Lender | Nominal rate | APR | Instalment | Balance after fixed period | Special repayment a year | Commitment-free period | Other costs |
|---|---|---|---|---|---|---|---|
| Your own bank | |||||||
| Bank 2 | |||||||
| Broker |
Work out an annuity loan in Excel
With one sheet and five formulas you can check any offer. The key figures go at the top:
| Cell | Content | Example |
|---|---|---|
| B1 | Loan | 400000 |
| B2 | Nominal rate a year | 4.10% |
| B3 | Initial repayment | 2% |
| B4 | Special repayment a year | 0 |
| B5 | Monthly instalment | =B1*(B2+B3)/12 gives €2,033.33 |
From row 8 the repayment schedule follows, one row per month. You fill in row 9 by hand and drag everything down from row 10 (about 400 rows):
| Column | Heading | Formula in row 9 | from row 10 |
|---|---|---|---|
| A | Month | 1 |
=A9+1 |
| B | Balance at start | =$B$1 |
=F9 |
| C | Interest | =B9*$B$2/12 |
drag down |
| D | Repayment | =MIN($B$5-C9,B9) |
drag down |
| E | Special repayment | =IF(MOD(A9,12)=0,MIN($B$4,B9-D9),0) |
drag down |
| F | Balance at end | =B9-D9-E9 |
drag down |
To check: month 1 gives €1,366.67 interest and €666.67 repayment, month 120 a balance of €301,314.12. Useful functions in English-language Excel:
=NPER(B2/12,-B5,B1)gives the term, here 326.9 months.=SUM(C9:C408)gives the total interest, here €264,779.=EFFECT(B2,12)gives the APR without fees, here 4.18%.=(1+IRR(payments))^12-1gives the APR including a discount or fees. Enter the payout as a plus in month 0, then the instalments, and the remaining balance as a minus at the end.
In German-language Excel the functions are called ZZR, SUMME, EFFEKTIV, IKV, WENN and REST, and the separator is a semicolon.
Everything in one picture: your financial compass
In real life every lever moves at once. In the OWNAMIC Big Picture, the loan, the household book, big expenses such as heating or roof, and scenarios such as parental leave or a sabbatical sit on one timeline. The remaining debt runs along as a dashed line. If the term you entered ends with debt left, the Big Picture keeps it constant from then on and marks the follow-up financing as "open — assumed". The data basis shows you what is still missing. You see the result as a corridor, also in today's purchasing power.
The Big Picture is your compass, the household book your rudder.
OWNAMIC gives no advice: no financial, investment, insurance or tax advice. The Big Picture carries your own entries forward and does not predict what will happen.
Try it free for 14 days, no payment details: ownamic.com/en/finances
Further reading: Run the numbers on parental leave · Carrying your net worth forward · Financial planning with OWNAMIC
Try it now
Free for 14 days, no payment details. All you need is your email address.
Registration is subject to our Terms and Conditions and Privacy Notice.
Sources
All example calculations are our own, for an invented household, as of October 2026. They are no substitute for financial, investment or insurance advice. Most sources are in German.
- Verbraucherzentrale NRW: Property financing – how to work out what you can afford
- Interhyp: BaFin concerned about current lending trends (06/2026, with data from AFS and the Bundesbank)
- WKO: FMA rules for private residential property financing (KIM regulation)
- § 16 Price Indication Ordinance (PAngV)
- Dr. Klein: Annual percentage rate
- leinetal24: Mortgage rates at a high (Biallo index, 10/2026)
- § 500 BGB and § 495 BGB
- Interhyp: Maintenance reserve
- Schwäbisch Hall: Maintenance reserve
- FIM portal: Service description parental benefit
- Stiftung Warentest: Sickness benefit
- gegen-hartz.de: Disability pension, figures from the DRV annual report 2025
- German Association of Actuaries (DAV): Aktuar Aktuell 44, occupational disability
- Verbraucherzentrale: Payment protection insurance is expensive and pays out little (09/2026)
- Richify: Wealth of renters vs. owners, based on Bundesbank PHF 2023
- Stiftung Warentest: Home financing field test, Finanztest 2/2023
- ODDO BHF: Consumer information on residential property loans (ESIS sheet)